This invention relates to video games, and more particularly to a method and system for limiting the number of machines on which a compatible video game cartridge or other software medium may be played.
One of the problems faced by manufacturers of video game machines, such as those sold under the trademarks Nintendo and Sega, is that companies which rent videotapes often rent video game cartridges as well. Instead of the manufacturer making multiple sales of cartridges to different persons who desire to play a particular game, fewer sales are made to a "video store" which then rents the cartridges to different customers. It is the video store which realizes the profit on multi-user play of a particular game rather than the machine manufacturer under whose authorization the cartridges are sold in the first place.
Machine manufacturers have developed techniques for preventing the copying of cartridges and even the manufacture of original game cartridges. Nintendo Co., Ltd., for example, provides a microprocessor in each of its cartridges for communicating with a similar microprocessor in each machine. The Nintendo security system requires for its effectiveness that the microprocessor not be duplicated by other manufacturers, and Nintendo has achieved considerable success with this system. The arrangement is described in Nakagawa U.S. Pat. No. 4,799,635 and Nakagawa et al. U.S. Pat. No. 4,865,321. However, while the Nintendo approach prevents the copying of software cartridges and even the distribution of original unauthorized software, it in no way limits the rental of cartridges by a retailer who purchases them in a legitimate way.